Suspended Particulate Matter Samples Research Articles

Abiotic degradation of highly branched isoprenoid alkenes and other lipids in the water column off East Antarctica

In some previous studies, the ratio between a di-unsaturated highly branched isoprenoid (HBI) lipid termed IPSO25 and a structurally related tri-unsaturated counterpart (HBI III) (viz. IPSO25/HBI III) has been used as a proxy measure of variable sea ice cover in the Antarctic owing to their production by certain sea ice algae and open water diatoms, respectively. To investigate this further, we quantified selected lipids and their photo- and autoxidation products in samples of suspended particulate matter (SPM) collected at different water depths in the polynya region west of the Dalton Iceberg Tongue (East Antarctica). The results obtained confirm the high efficiency of photo- and autoxidation processes in diatoms from the region. The systematic increase of the ratio IPSO25/HBI III with water depth in the current samples appeared to be dependent on the sampling site and was due to both (i) a relatively higher contribution of ice algae to the deeper samples resulting from their increased aggregation and therefore higher sinking rate, or (ii) a stronger abiotic degradation of HBI III during settling through the water column. Analyses of samples taken from the water-sediment interface and some underlying near-surface sediments revealed a further increase of the ratio IPSO25/HBI III, indicative of further differential oxidation of the more unsaturated HBI. Unfortunately, specific oxidation products of HBI III could not be detected in the strongly oxidized SPM and sediment samples, likely due to their lability towards further oxidation. In contrast, oxidation products of HBI III were detected in weakly oxidized samples of phytoplanktonic cells collected from Commonwealth Bay (also East Antarctica), thus providing more direct evidence for the involvement of photo- and/or autoxidation of HBI III in the region. This oxidative alteration of the ratio IPSO25/HBI III between their source and sedimentary environments might need to be considered more carefully when using this parameter for palaeo sea ice reconstruction purposes in the Antarctic.

Effect of water depth on the TEX86 proxy in volcanic lakes of northeastern China

The TEX86 index, based on the distribution of isoprenoid glycerol dialkyl glycerol tetraethers (iGDGTs), has been widely applied for reconstructing past sea surface temperature (SST). However, its successful application in lacustrine environments has been limited to certain large lakes in which aquatic Thaumarchaeota are thought be the dominant iGDGT producers. In small lakes, multiple factors, such as iGDGTs from soil and non-thaumarchaeotal sources, could complicate the use of TEX86 as a temperature proxy (Powers et al., 2010). Here we investigate iGDGTs from surface sediments and suspended particulate matter (SPM) in a series of small volcanic lakes (areas: ∼0.1–8.2 km2) from three main volcanic fields of northeastern China. The iGDGT distribution patterns from surface sediments of these lakes differ significantly from those of surrounding soils, global marine sediments, as well as cultured Group I.1a and Group I.1b Thaumarchaeota, suggesting a substantial contribution of autochthonous non-thaumarchaeotal sources. Interestingly, however, the correlation between TEX86 values in the SPM samples and in situ water temperatures remain strong and display temperature sensitivity similar to previously published linear calibrations from global marine and lake sediments. Our results suggest that the in situ TEX86-temperature relationship is little affected by the non-thaumarchaeotal iGDGT sources in these lakes. However, the TEX86-inferred temperatures from surface sediments show increasingly colder offsets relative to air temperatures with increasing lake depth, which can be explained by the observed increase in iGDGTs production and decrease in water temperatures in water column as depth increases. Our results thus suggest that TEX86 values in the sediments of these volcanic lakes are affected by both temperature and lake depth, and when temperature can be constrained independently or remains constant over a given period of time, have potential application as a lake level proxy in deep volcanic lakes.

Quantifying the impacts of artisanal gold mining on a tropical river system using mercury isotopes

In some locations, artisanal and small-scale gold-mining (ASGM) represents a significant source of anthropogenic Hg to freshwater environments. The Hg released from ASGM can contaminate aquatic fauna and pose health risks to downstream populations. Total Hg (THg) concentrations, speciation, and isotopic compositions were analyzed in water, suspended particulate matter, soil, and bottom sediment samples from pristine areas and in places of active and legacy gold mining along the Oyapock River (French Guiana) and its tributaries.Mass-independent fractionation (MIF) of even Hg isotopes in top soils (Δ200Hg = −0.06 ± 0.02‰, n = 10) implied the uptake of gaseous Hg(0) by plants, rather than wet deposition, as the primary Hg source. Odd isotope MIF was lower in deep soils (Δ199Hg = −0.75 ± 0.03‰, n = 7) than in top soils (Δ199Hg = −0.55 ± 0.15‰, n = 3). This variation could be attributed to differences between the isotopic signatures of modern and pre-industrial atmospheric Hg.Combining a Hg-isotope binary mixing model with a multiple linear regression based on physico-chemical parameters measured in the sediment samples, we determined that active mined creek sediments are contaminated by ASGM activities, with up to 78% of THg being anthropogenic. Of this anthropogenic Hg, more than half (66–74%) originates from liquid Hg(0) that is released during ASGM. The remaining anthropogenic Hg comes from the ASGM-driven erosion of Hg-rich soils into the river. The isotope signatures of anthropogenic Hg in bottom sediments were no longer traceable in formerly mined rivers and creeks.

Combining flux monitoring and data reconstruction to establish annual budgets of suspended particulate matter, mercury and PCB in the Rhône River from Lake Geneva to the Mediterranean Sea

Long term and high resolution data on water discharge, suspended particulate matter (SPM) and contaminant concentrations in rivers are required for a better understanding of particulate transfers from the continental areas to the seas. The aim of this study was to provide a novel estimation of annual fluxes of SPM and related pollutants in the Rhône River from Lake Geneva to the Mediterranean Sea by combining high frequency or time-integrative monitoring and novel relations between SPM concentration (Cs) and water discharge (Q). At six stations of the Rhône Sediment Observatory (OSR), SPM fluxes were calculated over the 2000–2016 period by combining observational data and Cs-Q relations. Monthly average concentrations of mercury (Hg) and PCB 180 were obtained by analysis of SPM samples collected in time integrative particle traps between 2011 and 2016. These pollutants were selected because of the well documented contamination of the Rhône watershed by these substances. Inter-annual fluxes at the Rhône River outlet averaged 6.6 Mt. yr−1 for SPM, 572 kg yr−1 for Hg and 14 kg yr−1 for PCB 180. The Isère and Durance tributaries were found to be the main contributors of SPM fluxes. Annual SPM budgets were not balanced, suggesting deposition, remobilization of bottom sediments and/or contributions from non-monitored tributaries. The SPM sampled at the outlet was more contaminated than the combined SPM inputs from the monitored tributaries, suggesting that intermediate sources of contamination were not captured in the budget.

Air pollution of beauty salons by cosmetics from the analysis of suspensed particulate matter

Beauty salons make a considerable part of the service sector. However, although the beauty salon staffs are exposed to a vast number of ambient chemicals during the whole workday, the occupational health hazard and the indoor air quality in beauty salons are poorly known. Specifically, reports on relations between indoor particulate matter and its outdoor or indoor sources in beauty salons are rare. Here we studied the effects of external and internal sources of aerosol in beauty salons on indoor ambient particulate matter and on its elemental and organic carbon contents. We selected four beauty salons differing in the number and type of particulate matter indoor and outdoor sources. The approach consisted in taking ten eight-hour samples of total suspended particulate matter and ten samples of its respirable sub-fraction simultaneously indoors and outdoors at each site, then analyzing them for carbon content using a thermo-optical method. The ambient concentrations of particulate matter and organic carbon were higher indoors than outdoors. We show that differences between indoor and the outdoor concentrations is due to the indoor use of cosmetics and other human activity. The effects of indoor sources on indoor elemental carbon concentrations are lower than on organic carbon concentrations.

Features of the Elemental Composition of Aral Sea Suspended Matter in Modern Conditions

The paper presents the first data on the contents of 22 macro- and microelements in marine suspended particulate matter (SPM) since the Aral Sea began to dry in 1961. The concentration of SPM in the western basin is low and fluctuates within a narrow range of 0.2 to 1.14 mg/L, on average, around 0.7 mg/L for 16 samples. Microscope studies have shown the presence of microparticles of different origin in SPM. Among the biogenic particles are diatomic opal frustules, individual coccoliths, plant pollen, etc. Terrigenous minerals are represented by grains of quartz, feldspars, amphiboles, pyroxenes, and clay aggregates. Chemogenic minerals include crystals of gypsum, celestine, and strontianite. Examination of unfiltered water under an optical microscope showed the presence of gypsum crystals, which points to authigenic mineral formation directly in the water column. The ICP-MS method (Agilent 7500) was used to analyze 11 samples of SPM from the 0–10 m layer (oxygenated waters) and five samples from the 18–38 m horizon (hydrogen sulfide water). With respect to the clay/shale global mean values, Aral Sea SPM is depleted in lithogenic Fe, Al, Ti, and Mg and somewhat enriched in Na and Mn. Comparison with data on the contents of the same elements in present-day Aral Sea sediments [1] has shown that SPM is notably poorer in bottom sediments of Ca, Mg, Fe, and M and enriched in Mn. With respect to clays/shales, Aral Sea SPM from oxygenated waters is enriched in Cu, Ni, Mo, Pb, and W (by 1.5–4.0 times), whereas SPM in the entire water column is notably depleted in Cr, Be, V, Zr, and Ta. Mo is sharply distinguished, with SPM from hydrogen sulfide waters enriched 37-fold; there are two reasons for this: hydrogen sulfide contamination and high water mineralization.

Trace element composition of suspended particulate matter along three meridional CLIVAR sections in the Indian and Southern Oceans: Impact of scavenging on Al distributions

We present the trace element composition (Al, Si, P, Ca, Fe, and Zn) of suspended particulate matter (SPM) samples collected in the upper 1000 m along U.S. CLIVAR/CO2 Repeat Hydrography meridional section I09N/I08S from the Southern Ocean to the Bay of Bengal at 95°E and in surface waters along meridional section I06S from the South African margin to the Antarctic shelf edge at 30°E. A band of elevated surface-ocean pCa (0.5–0.3 μM) over 30–60°S is consistent with the global pattern of high coccolithophore production encircling the Southern Ocean suggested by remote sensing. Over 50–60°S, both sections exhibit a sharp transition from Ca-rich to Si-rich particulate matter (up to 2.8–6.5 μM), indicating a change from coccolithophore to diatom communities in waters with low residual nitrate. Along I08S, diatom blooms display elevated pZn concentrations and Zn:P ratios (14.9 + 5.7 mmol mol−1), reflecting cellular Zn stoichiometry of Southern Ocean diatoms. Regions of high primary productivity in the Southern Ocean are coincident with unexpectedly high surface-ocean pAl concentrations (max 12.6–26.5 nM) compared to background concentrations (typically <2 nM along I09N/I08S and <5 nM along I06S). We estimate that >50% of surface-ocean pAl in these regions originates from adsorptive scavenging of dissolved Al onto biogenic particles. Along I08S, dissolved Al reservoirs likely originate from transport of Al-enriched waters by the Agulhas Return Current, local dust deposition, and seasonal ice melt. Along I06S, pAl distributions suggest larger inputs of dust to the surface mixed layer than have previously been described. By contrast, pFe concentrations remain low in both surface (<0.3 nM I09N/I08S, 0.1–0.8 nM I06S) and intermediate (<0.4 nM I09N/I08S) waters away from coastal and shelf inputs. Inputs of lithogenic material from resuspended shelf sediments are apparent in the distributions of pFe and pAl close to the Antarctic margin (up to 10 nM pFe and 23.4 nM pAl) and the South African coast (up to 3.1 nM pFe and 8 nM pAl). At intermediate depths along I08S, elevated pFe concentrations (up to 1.0 nM) are observed downstream of the Kerguelen Plateau, reflecting lateral transport of resuspended plateau sediments or glacial runoff.This article is part of a special issue entitled: Cycles of trace elements and isotopes in the ocean – GEOTRACES and beyond.

Distribution, Behavior, and Sources of Polycyclic Aromatic Hydrocarbon in the Water Column, Sediments and Biota of the Rufiji Estuary, Tanzania

To establish the environmental status of Rufiji coastal waters in Tanzania, it is necessary to document the different contaminants as major entry points into the lower estuarine areas. Because there is no data on polycyclic aromatic hydrocarbon (PAH) contamination in this estuarine delta, the current study measured the concentrations of 19 PAHs in suspended particulate matter (SPM), surface sediments and marine organisms that are part of a telescoping food chain (gastropod Terebralia sp., clams Crassostrea cucullata, crabs Uca sp., panaeid shrimps Panaeus monodon, teleost Hilsa kelee, Trichiurus lepturus, and Arius thalassinus). Total PAH concentrations in SPM were low to moderate (18.7–223 ng/g) and varied between the sites; phenanthrene and chrysene were the dominant PAHs (2.40–47.2 and 4.20–28.1 ng/g, respectively). Significant variation between the sites indicates the influence of fuel spills and contribution from terrestrial sources resulting from different land use practices, such as agriculture, fishing, and harvesting firewood, charcoal, and mangroves poles. PAH concentrations in surface sediments were higher (127–376 ng/g) than SPM samples, and high molecular weight PAHs were the dominant fraction. Animal tissues indicated low PAH levels (9.20–158 ng/g). Only low molecular weight PAHs were dominant in the muscle tissues of pelagic and filter feeders (C. cucullata, P. monodon, and H. kelee). Bioaccumulation factor (BAF) ranged between 0.20 and 69.5 and it suggests 1) PAH accumulation in the marine organisms has so far been limited, and 2) distribution of PAHs in the Rufiji estuary poses limited risks.

Sampling of suspended particulate matter using particle traps in the Rhône River: Relevance and representativeness for the monitoring of contaminants

Monitoring hydrophobic contaminants in surface freshwaters requires measuring contaminant concentrations in the particulate fraction (sediment or suspended particulate matter, SPM) of the water column. Particle traps (PTs) have been recently developed to sample SPM as cost-efficient, easy to operate and time-integrative tools. But the representativeness of SPM collected with PTs is not fully understood, notably in terms of grain size distribution and particulate organic carbon (POC) content, which could both skew particulate contaminant concentrations. The aim of this study was to evaluate the representativeness of SPM characteristics (i.e. grain size distribution and POC content) and associated contaminants (i.e. polychlorinated biphenyls, PCBs; mercury, Hg) in samples collected in a large river using PTs for differing hydrological conditions. Samples collected using PTs (n = 74) were compared with samples collected during the same time period by continuous flow centrifugation (CFC).The grain size distribution of PT samples shifted with increasing water discharge: the proportion of very fine silts (2–6 μm) decreased while that of coarse silts (27–74 μm) increased. Regardless of water discharge, POC contents were different likely due to integration by PT of high POC-content phytoplankton blooms or low POC-content flood events. Differences in PCBs and Hg concentrations were usually within the range of analytical uncertainties and could not be related to grain size or POC content shifts. Occasional Hg-enriched inputs may have led to higher Hg concentrations in a few PT samples (n = 4) which highlights the time-integrative capacity of the PTs. The differences of annual Hg and PCB fluxes calculated either from PT samples or CFC samples were generally below 20%. Despite some inherent limitations (e.g. grain size distribution bias), our findings suggest that PT sampling is a valuable technique to assess reliable spatial and temporal trends of particulate contaminants such as PCBs and Hg within a river monitoring network.

Widespread occurrence of distinct alkenones from Group I haptophytes in freshwater lakes: Implications for paleotemperature and paleoenvironmental reconstructions

Alkenones are C35–C42 polyunsaturated ketone lipids that are commonly employed to reconstruct changes in sea surface temperature. However, their use in coastal seas and saline lakes can be hindered by species-mixing effects. We recently hypothesized that freshwater lakes are immune to species-mixing effects because they appear to exclusively host Group I haptophyte algae, which produce a distinct distribution of alkenones with a relatively consistent response of alkenone unsaturation to temperature. To evaluate this hypothesis and explore the geographic extent of Group I haptophytes, we analyzed alkenones in sediment and suspended particulate matter samples from lakes distributed throughout the mid- and high latitudes of the Northern Hemisphere (n=30). Our results indicate that Group I-type alkenone distributions are widespread in freshwater lakes from a range of different climates (mean annual air temperature range: −17.3–10.9 °C; mean annual precipitation range: 125–1657 mm yr−1; latitude range: 40–81°N), and are commonly found in neutral to basic lakes (pH > 7.0), including volcanic lakes and lakes with mafic bedrock. We show that these freshwater lakes do not feature alkenone distributions characteristic of Group II lacustrine haptophytes, providing support for the hypothesis that freshwater lakes are immune to species-mixing effects. In lakes that underwent temporal shifts in salinity, we observed mixed Group I/II alkenone distributions and the alkenone contributions from each group could be quantified with the RIK37 index. Additionally, we observed significant correlations of alkenone unsaturation (U37K) with seasonal and mean annual air temperature with this expanded freshwater lakes dataset, with the strongest correlation occurring during the spring transitional season (U37K=0.029⁎T−0.49; r2=0.60; p<0.0001). We present new sediment trap data from two lakes in northern Alaska (Toolik Lake, 68.632°N, 149.602°W; Lake E5, 68.643°N, 149.458°W) that demonstrate the highest sedimentary fluxes of alkenones in the spring transitional season, concurrent with the period of lake ice melt and isothermal mixing. Together, these data provide a framework for evaluating lacustrine alkenone distributions and utilizing alkenone unsaturation as a lake temperature proxy.

Forms of phosphorus in suspended particulate matter in agriculture-dominated lowland catchments: Iron as phosphorus carrier

The fate and environmental effects of phosphorus (P) in natural waters depend on its chemical forms. The particulate P (PP) concentration is dominant over the dissolved P concentration in agriculture-dominated headwaters in the Netherlands. Routine water quality monitoring programmes do not include the chemical fractionation of PP. To quantify the chemical forms of PP under various conditions in six agriculture-dominated lowland catchments in the Netherlands, a sequential chemical extraction method was applied to suspended particulate matter (SPM) samples collected by centrifugation or filtration. Centrifuge samples had lower values for the sum of the PP fractions compared with the filtration samples due to lower contents from PP fractions other than the Fe-P pool. With an average value of 8.8mgg−1, internationally high P contents of the SPM were found. Ferric iron-bound P was the most important PP fraction in SPM samples (38–95%; median 74%), followed by organic P (2–38%; median 15%). Exchangeable P ranged from 0.2 to 27%, with a median of 4.4%, Ca-P ranged from 0.1 to 11% with a median of 3.9% and detrital P was present in only a small fraction (0–6%; median 1.1%). Ferric iron-bound P was the dominant PP pool throughout the entire range of watercourses (from headwater ditches to catchment outlets) and in samples taken during winter months as well as those taken during summer months. Furthermore, the PP fraction distribution did not change markedly when flow conditions were altered from low to high discharge. The dominance of the Fe-P pool denotes the presence of Fe(III) precipitates in SPM that originate from exfiltration of anoxic Fe-bearing groundwater. These Fe(III) precipitates are a major fraction of the total SPM concentration (4 to 67% as Fe(OH)3; median 18%). Although not measured directly, our results suggest that formation of authigenic Fe(III) precipitates causes a rapid transformation of dissolved P in groundwater to PP in surface water. We advise including sequential chemical extraction of SPM monitoring programmes because the composition of particles is critical for P bioavailability, which is a key driving factor for eutrophication.

Investigation of pharmaceutically active compounds in an urban receiving water: Occurrence, fate and environmental risk assessment

Pharmaceutically active compounds (PhACs) recently have been recognized to constitute a health risk for aquatic ecosystems. The major pathways of PhACs to enter the aquatic environment are excretion and discharge of effluents through sewage treatment plants (STPs). The occurrence, bioaccumulation and risk assessment of lipophilic PhACs, including erythromycin, ketoconazole, indomethacin, diclofenac, gemfibrozil, bezafibrate, propranolol, carbamazepine, sertraline and 17α-ethinylestradiol were investigated in a river that receives effluents from STP. The results indicate that the PhACs were extensively existed in fish, sediment, suspended particulate matter (SPM), colloidal phase (5 kDa to 1 µm) and truly dissolved phase (< 5 kDa) water, with total concentration of ten PhACs (Σ10PhACs) of ND-19.6 ng/g, 7.3–11.2 ng/g, 25.3–101.5 ng/g, 10.1–27.7 ng/L and 67.0–107.6 ng/L, respectively. The Σ10PhACs for particulate and water samples collected from STP's outfall site were higher than those collected from upstream and downstream, indicating that the STP is an important PhACs source of river. However, the Σ10PhACs in sediment showed no significant statistical differences in the sampling area, and which was 3.5–9.5 times lower than those in SPM samples. The colloidal phase contributed 2.5–28.5% of erythromycin, 5.8–45.6% of ketoconazole, 8.4–32.2% of indomethacin, 7.0–21.4% of diclofenac, 11.6–36.9% of gemfibrozil, 10.2–45.9% of bezafibrate, 5.9–16.8% of propranolol, 1.9–11.1% of carbamazepine and 1.1–23.8% of sertraline in the aquatic environment. This suggests that aquatic particulates (e.g., colloids and SPM) maybe an important carrier for PhACs in the aquatic system. In general, the Σ10PhACs in the tissues of fish were in order as follows: kidney > brain > liver > gill > muscle. Based on truly dissolved concentrations of PhACs in the water, bioaccumulation factors were between 3.7 and 2727.3 in the fish tissues, sertraline exhibited bioaccumulation potential. In all the risk assessments, erythromycin could cause most harmful adverse health effects for the most sensitive algae group based on the acute and chronic data. In addition, the risk quotient values for diclofenac toward fish were higher than 1. These results indicate that the PhACs pose a potential risk to the aquatic organisms, especially for chronic risk.

Occurrence and levels of glyphosate and AMPA in shallow lakes from the Pampean and Patagonian regions of Argentina

Glyphosate (N-(phosphonomethyl)glycine) is a broad-spectrum systemic herbicide used to kill weeds that compete with commercial crops. In Argentina, the use of glyphosate-based herbicides increased dramatically (up to ∼200,000 tons on 2012) since the introduction of glyphosate-resistant crops, such as transgenic soy and resistant corn, and the adoption of non-till practices in the 1990′s. Sallow lakes within the Pampa region may be potentially impacted by continuous herbicide usage. We surveyed 52 shallow lakes from the Pampa region (Buenos Aires Province, Argentina) to assess the occurrence and concentrations of glyphosate and its main degradation product (AMPA). For comparison, we also sampled 24 shallow lakes from an area with no agricultural use of glyphosate (Northern Patagonia). Glyphosate and AMPA were analyzed by UPLC-MS/MS ESI (±) in lake water, suspended particulate matter (SPM), and sediment samples. Within the Pampa region, glyphosate residues were detected in >40% of samples. Glyphosate residues were detected more frequently in sediment and surface water than in SPM samples. The mean (maximum) concentrations of glyphosate were 2.11 (4.52) μg l−1 for surface water; 0.10 (0.13) μg l−1 for SPM and 10.47 (20.34) μg kg−1 for sediment samples, respectively. Whereas, mean (maximum) concentrations of AMPA were 0.84 and (0.90) μg l−1 for surface water; 0.07 (0.07) μg l−1 for SPM; and 22.53 (32.89) μg kg−1 for sediment samples. The herbicide was not detected in samples from the Patagonian region. To our knowledge, this is the first study reporting the occurrence and concentrations of the herbicide in freshwater lakes of Argentina.

Distribution of long chain alkyl diols along a south-north transect of the northwestern Pacific region: Insights into a paleo sea surface nutrient proxy

Long chain alkyl diols (LCDs) have previously been used to develop several diol indices as a proxy for upwelling or stratification conditions and sea surface temperatures. However, there is still a lack of data on the distribution of LCDs in the Pacific Ocean, which calls into question to what extent these diol indices can serve as a proxy in the Pacific Ocean. Hence, we investigated the distribution of LCDs in suspended particulate matter (SPM) samples collected in July 2015 along a south-north transect ranging from the East Sea of Korea to the Bering Sea in the northwestern Pacific region. Our results showed that both saturated and unsaturated C28 and C30 1,14-diols were dominant in most SPM samples investigated. The principal component analysis (PCA) results of the SPM data revealed that the C28:1 and C30:1 1,14-diols were positively associated with nutrient concentrations. However, only the C28:1 1,14-diol in addition to the C28 1,14-diol was positively associated with nutrient concentrations in the global surface sediment data set previously published, while the C30:1 1,14-diol was related to sea surface temperature (SST). Based on these observations, we defined a new diol index, i.e., the nutrient diol index (NDI), which included the C28 1,14-diol as well as the C28:1 1,14-diol in the numerator and all the 1,13-, 1,14-, and 1,15-diols, excluding the C32 1,15-diol, in the denominator. The NDI was positively associated with the ocean atlas values of surface water phosphate and nitrate concentrations for the SPM and surface sediment data sets. Accordingly, the results of our study showed that the NDI has potential as a quantitative nutrient proxy for estimating sea surface phosphate (or nitrate) changes. Further studies should be undertaken in order to assess the applicability of the NDI as a paleo-nutrient proxy for confidently reconstructing surface water nutrient variations in the past, by analyzing more SPM, surface sediments, and sediment cores collected from various oceanic settings.

Trace metals concentration assessment in urban particulate matter in Yenagoa and its environs

This study was conducted to investigate the distribution and correlation of selected trace elements (Ca, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in Yenagoa, Bayelsa State and its environs. Air particulate matter was collected gravimetrically at five stations (using a high volume portable SKC air check MTXSidekickair sampler (Model: 224-52MTX). The total suspended particulate matter samples were extracted in nitric acid and hydrochloric acid mixture, followed by the quantification of the trace elements by flame Atomic Absorption Spectrophotometric (AAS) method (Model: AA 6600, GBC Avanta PM AAS). The estimated elemental data were then subjected to a set of Multivariate statistical analysis and evaluated for their mutual variations in the urban particles. The concentrations of trace elements (μgm-3) found in the particulate matter were in the order of Ca&gt;Fe&gt;Zn&gt;Ni&gt;Pb&gt; Mn&gt;Cu&gt;Cd&gt;Co&gt;Cr. On the average, the correlation of the trace elements of the study area shows strong correlations between Pb-Ni, Fe-Mn, Co-Ni, Zn-Pb, with correlation coefficients of 0.767, 0.595, 0.508, and 0.791 respectively. Principal component analysis revealed that major sources of trace metals in ambient air of the study areas were mainly emissions from automobile exhaust, industrial emissions and gas flaring.Keywords: Particulate matter, trace elements, enrichment factor, toxic

Dioxins, furans and dioxin-like PCBs in sediment samples and suspended particulate matter from the Scheldt estuary and the North Sea Coast: Comparison of CALUX concentration levels in historical and recent samples

BackgroundThe Scheldt estuary is historically a highly polluted river system. While several studies have focused on contamination with metals, pesticides, Polycyclic Aromatic Hydrocarbons (PAHs) and marker PolyChlorinated Biphenyls (PCBs), no data are available concerning past contamination by dioxin-like compounds. ObjectivesThe objective of this study is to determine spatial and time trends of PolyChlorinated Dibenzo-p-Dioxins and DibenzoFurans (PCDD/Fs) and dioxin-like PCBs (dl-PCBs) in sediment samples and Suspended Particulate Matter (SPM) from the Scheldt River basin and the North Sea Coast. MethodsDioxin-like compounds (PCDD/F and dl-PCB fractions) were measured with the CALUX-bioassay. Bioanalytical EQuivalent concentrations (BEQs) and Total Organic Carbon (TOC) content of historical (1982–1984) and recent (2011–2015) sediment and SPM samples from different locations in the coastal area and the estuary, were evaluated. ResultsA decrease in dioxin-like compound concentrations was found at all stations over time, especially for the PCDD/Fs. Dl-PCBs were relatively low in all samples. The Scheldt mouth and the Antwerp harbor yielded the highest BEQs and levels were higher in SPM than in sediment due to the higher organic carbon content in this fraction. ConclusionsCurrent PCDD/F and dl-PCB levels in the Belgian Coastal Zone and Scheldt estuary are much lower than their levels 30 years ago and pose a relatively low risk to the aquatic system. This is the result of a strong decrease in emissions, however, large local variabilities in sediment concentration levels can still exist because of local variability in sedimentation, erosion rates and in organic carbon content.

Spatio-temporal evaluation of emerging contaminants and their partitioning along a Brazilian watershed.

The occurrence, partitioning, and spatio-temporal distribution of seven pharmaceuticals for human use, three steroid hormones and one personal care product were determined in surface water, suspended particulate matter (SPM), and sediment of Piraí Creek and Jundiaí River (Jundiaí River Basin, São Paulo, Brazil). The maximum average detected concentrations of the compounds in the Piraí River samples were < 30ngL-1, except for caffeine (222ngL-1). In Jundiaí River samples, most of the compounds were frequently detected, wherein caffeine had the highest concentration, with maximum average concentrations of 14,050ngL-1, followed by atenolol (431ngL-1), ibuprofen (268ngL-1) and diclofenac (214ngL-1). Atenolol, propranolol, estrone, and triclosan were the contaminants most frequently detected in sediment and SPM samples. Triclosan had the highest average proportion of SPM as opposed to in the aqueous phase (> 75%). Contaminants with acid functional groups showed, in general, a lower tendency to bind to particulate matter and sediments. In addition, hydrophobicity had an important effect on their environmental partitioning. The spatial distribution of contaminants along the Jundiaí River was mainly affected by the higher concentration of contaminants in water samples collected downstream from a sewage treatment plant (STP). The results obtained here clearly showed the importance of the analysis of some contaminants in the whole water, meaning both dissolved and particulate compartments in the water, and that the partitioning is ruled by a set of parameters associated to the physicochemical characteristics of contaminants and the matrix properties of the studied, which need be considered in an integrated approach to understand the fate of emerging chemical contaminants in aquatic environments.

Biomonitoring of Atmospheric Polycyclic Aromatic Hydrocarbons: A Mini Review

Background: A number of atmospheric pollutants, such as polycyclic aromatic hydrocarbons, volatile organic compounds, and heavy metals, are monitored by environmental researchers. Among these atmospheric pollutants, polycyclic aromatic hydrocarbons play an important role owing to their nature, which is carcinogenic and toxic to human beings. A number of researchers have monitored these atmospheric pollutants using active and passive samplers, and a few have monitored their concentrations using biological specimens such as lichens and mosses. Method: We reviewed the biomonitoring of atmospheric polycyclic aromatic hydrocarbons using various biological specimens. For this purpose, we examined nearly 35 research papers published since 2013 in various reputed international journals. From this study, it is clear that biological specimens are useful for monitoring the concentrations of atmospheric polycyclic aromatic hydrocarbons. Results: A number of PAHs exist in the atmosphere, but according to the United States Environmental Protection Agency (US EPA), only the following 16 are considered priority PAHs due to the availability of data and their carcinogenic and toxic nature: Napthalene (Nap), Acenaphthylene (Acy), Acenaphthene (Acp), Fluorene (Flu), Phenanthrene (Phe), Anthracene (Ant), Fluoranthene (Flt), Pyrene(Pyr), Benz[a]anthracene (BaA), Chrysene(Chry), Benzo[b]fluoranthene (BbF), Benzo [k]fluoranthene (BkF), Benzo[a]pyrene(BaP), Indeno [1,2,3-cd]pyrene(IcdP), Dibenz[a,h]anthracene (DahA), and Benzo[ghi] perylene(BghiP). These PAHs are collected by various procedures, such as active sampling of total suspended particulate matter and PM2.5, and passive sampling. Along with these conventional methods, biological species are also used to monitor PAHs. In this study, we reviewed research papers published since 2013 that described the monitoring of atmospheric PAHs with a number of biological materials such as lichens, mosses, and other plant materials. Conclusion: Based on the review, we conclude that several researchers have successfully used biological materials to monitor the levels of atmospheric PAHs in different countries and from different sampling sites. However, the data obtained in these studies can be reliable only when they are compared with conventional instrumental methods. Most of the studies compare their results with those obtained from either active or passive air sampling methods. The major advantage of biomonitoring studies is the low cost of sampling and that provides reasonably reliable data. Keywords: Biomonitoring, polycyclic aromatic hydrocarbons, air pollutants, atmospheric pollutants, volatile organic compounds, biological specimen.

Isoprenoid tetraether lipids in suspended particulate matter from the East China Sea and implication for sedimentary records

A total of 90 samples of suspended particulate matter (SPM) collected in surface waters of the East China Sea (ECS) in summer and winter were studied for archaeal isoprenoid glycerol dialkyl glycerol tetraether lipids (iGDGTs) and the derived sea surface temperature (SST) proxy, i.e. TEX86H. Our data showed that in summer SPM TEX86H correlated well with in-situ measured SST, but in winter the relationship became much poorer. We found that the bottom water depth (BWD) of 70 m was a critical depth when studying the TEX86H-SST relationship in winter SPM. In locations with BWD < 70 m, concentrations of iGDGTs in SPM were > 5x higher in winter than in summer, but TEX86H showed a much weaker correlation with in-situ measured SST. This was speculated to be caused by lateral transport of SPM and resuspension of surface sediments in winter due to strong winds. Whereas in locations with BWD > 70 m, TEX86H correlated well with in-situ measured SST, suggesting a minor influence of SPM lateral transport and sediment resuspension. Moreover, although only core iGDGTs were analyzed, we found that both summer and winter TEX86H values correlated better with in-situ measured SST than with seasonal and annual mean SST, suggesting that SPM iGDGTs were dominantly produced around the sampling time rather than encompassing longer time input. The linear relationships of SPM TEX86H with in-situ measured SST were different between winter (BWD > 70 m) and summer, likely due to seasonal archaeal community change. Published sedimentary TEX86H data in the ECS were reexamined here, and a BWD of 70 m was also found to be a critical depth. At sites with BWD > 70 m, TEX86H in sediments correlated well with annual mean SST, whereas the correlation became poor at BWD < 70 m, suggesting that sedimentary GDGTs were also greatly influenced by resuspension and lateral transport, and hence complicating the application of the proxy to shallow locations in the ECS.

Occurrence and distribution of marine natural organic pollutants: Lipophilic marine algal toxins in the Yellow Sea and the Bohai Sea, China

For the first time, the composition, concentration and distribution characteristics of typical lipophilic marine algal toxins (LMATs) are investigated in surface seawater, suspended particulate matter (SPM) and sediments from the Yellow Sea and the Bohai Sea, China. Pectenotoxin-2 (PTX2) and okadaic acid (OA) were detected in offshore surface seawater samples (n=67) of the Yellow and Bohai Seas, and PTX2 was found in higher concentrations than OA. The concentrations of PTX2 were between 0.49 and 14.14ng/L. OA, dinophysistoxin-1(DTX1), PTX2 and gymnodimine (GYM) were detected in the nearshore surface seawater samples (n=20) of the Haizhou Bay of the Yellow Sea. OA concentrations were between 11.47 and 55.85ng/L. There was a large degree of variation in the concentrations of DTX1, from <limit of quantification (LOQ) up to 143.14ng/L. The nearshore surface seawater samples (n=13) obtained from the Longdao area of the Bohai Sea mainly contain OA (5.00–24.14ng/L) and DTX1 (1.52–49.39ng/L), with PTX2 concentrations being less than the LOQ. Several LMATs were also detected both in the SPM and sediment samples of each study area. In summary, the LMAT composition and concentration levels in the surface seawater found in nearshore samples were substantially different from those of samples from the distant shore, which indicated the obvious regional characteristics of LMATs according to their spatial distribution in the Yellow Sea and the Bohai Sea.